Humoral Immunity Flashcards

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1
Q

Humoral immunity

Mediated by ________, also called _______, produced by _______ cells.

A

antibodies (Ab)

immunoglobulin (Ig); Plasma

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2
Q

Antibodies generally are found in _____cellular fluids

Eg ____,____,_______

A

extra

Blood, lymph, mucus

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3
Q

Antibodies are active against agents with an __________ phase, including some viruses, toxins, and bacterial infections

A

extracellular

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4
Q

Plasma cells are derived from activated ______ that are produced in the _______

A

B-cells

bone marrow

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5
Q

B cells
B cells display a single homogenous clonal immunoglobulin molecule on their surface.
These immunoglobulins serve as receptors (B-cell receptors [BCRs]) for a specific antigen
Each B cell can respond to only one antigen or a closely related group of antigens.
All immature B cells carry IgM immunoglobulins on their surface
B cells also have surface receptors for the Fc portion of immunoglobulins and for several complement components.

A
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6
Q


• • •
B cells
B cells display a single homogenous clonal immunoglobulin molecule on their surface.
These immunoglobulins serve as receptors (B-cell receptors [BCRs]) for a specific antigen
Each B cell can respond to only one antigen or a closely related group of antigens.
All immature B cells carry IgM immunoglobulins on their surface
B cells also have surface receptors for the Fc portion of immunoglobulins and for several complement components.

A
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7
Q

B cells

B cells display a single _____genous clonal immunoglobulin molecule on their surface.

These immunoglobulins serve as receptors (——————-) for a specific antigen

Each B cell can respond to only ______ antigen or a ___________ of antigens.

A

homo

B-cell receptors [BCRs]

one ; closely related group

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8
Q

All immature B cells carry Ig____ immunoglobulins on their surface

B cells also have surface receptors for the _______ of immunoglobulins and for several complement components.

A

M

Fc portion

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9
Q

An antigen interacts with the B lymphocyte that shows the best “______” by virtue of its immunoglobulin surface receptor.

The antigen binds to this BCR, and the B cell is stimulated to _________ and_______

The BCR with its bound antigen is _______ by the B cell and the antigen is ______________ that are then ___________________

A

fit

divide and form a clone (clonal selection).

internalized; degraded to yield peptides
returned to the cell surface bound to MHC class II molecules.

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10
Q

B cell receptor

MHC class ___– peptide complex on B cells is recognized by antigen-specific ________ cells.

CD____ ligand on T cells binds to CD___ on B cells, and the T cell produces cytokines, such as, _____,______,_____ which induce B-cell proliferation.

A

II; helper (CD4) T

40; 40

IL-4, IL-5, and IL-6,

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11
Q

Bcell receptor

Activated B cells migrate into ______ and proliferate to form __________ that now differentiate into either ________________ cells or ________ cells.

A

follicles

germinal centers

antibody-producing plasma

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12
Q

Structure of an Antibody Structure of an Antibody

Antibody composed of ______ chains and _______ chains.

These chains bind together to make a ____ shaped molecule

A

two heavy

two light

Y

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13
Q

The structure of Antibodies may be described by the way they are ___________ by _______.

The stem portion is referred to as the _________

The Y portion with the top third of the stem is referred to as the _____ region.

A

cut and digested; proteases

Fc region

Fab

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14
Q

Antibodies

The FC region often acts as the _____ for phagocytes during _______ or ______________ cytotoxicity.

The Fab region contains the ————- region

A

receptor

opsonisation

Antibody dependent cell mediated

antigen binding

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15
Q

The structure of Antibodies

The two sections located at the ends of Y’s arms are called ________ regions.

The variable region is structurally _______ for all ______________________

A

variable (V)

identical

antibodies synthesized by a particular plasma cell.

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16
Q

The Antibodies from each plasma cell however are different or unique from all other antibodies produced by other plasma cell.

T/F

A

T

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17
Q

Structure of antibodies

The stem of the antibody molecule as well as the lower portion of the arms called ————— regions.

Most H chains consist of _______ domain (VH) and _________ constant domains (CH).

A

constant (c)

one variable

three or more

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18
Q

Structure of antibodies

Variable regions are responsible for _____________

constant regions are responsible for the __________ described below:

All plasma cells in the body are _______________

A particular plasma cell may _______________________ producing in order to fight an infection in a different way.

A

antigen binding

biologic functions

producing one of these classes of antibodies.

switch the particular class of Antibody that it is

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19
Q

Ig___ is the first and main immunoglobulin produced early in the primary immune response.

A

M

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20
Q

IgM

IgM is present on the surface of virtually _____________ B cells.

It is composed of __________ units (each similar to one Ig____ unit) and ____ molecule of _____ chain

_______mer

____ units held together by _____ bonds

A

all uncommitted

five H2L2 ; G

one; J (joining)

Penta

5; disulfide

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21
Q

IgM

________ chain functions in the polymerization of monomers

Has _____ anitgen binding sites

A

J (Joining)

10

22
Q

Ig______ has the Highest binding capacity and cross linking of all immunoglobulin

A

M

23
Q

Ig____ is Most efficient immunoglobulin in agglutination, complement fixation, and other antigen–antibody reactions

A

M

24
Q

IgM

IgM does not cross the placenta

T/F

A

T

25
Q

IgM

Presence of IgM antibody in the fetus or newborn provides evidence of _______________

immunoglobulins

A

intrauterine infection.

26
Q

IgG

Most abundant isotype in serum (____ %)

Predominant antibody in ______ immune responses and constitutes an important defense against ______ and ———.

Cross placenta and play important role in ________

A

80

secondary

bacteria and viruses

protecting fetus

27
Q

Ig____ is the Most abundant isotype in serum

A

G

28
Q

IgG

— Provides (active or passive?) immunity to unborn fetus.

– Placental cells bind the ______ of IgG and transfer —— across the placental membrane.

Made up of four subclasses (_____,_____,______,_______)

A

Passive ; Fcportion; Ab

IgG1, IgG2, IgG3, IgG4

29
Q

IgG

Mediates opsonization of antigen through binding of __________ to _________ on macrophages.

Activate complement system _____-______

A

antigen-antibody complexes

Fc receptors

Opsonin—phagocytosis

30
Q

The main immunoglobulin responsible for mucosal immunity
It is found in secretions such as milk, saliva, and tears and in other secretions of the respiratory, intestinal, and genital tracts.
It protects mucous membranes from attack by bacteria and viruses
Plasma cells that release IgA Abs are concentrated along the Mucus Membrane surface.
Provides passive immunity to infants through mothers breast milk

A
31
Q

IgA

It is found in secretions such as milk, saliva, and tears and in other secretions of the respiratory, intestinal, and genital tracts.

T/F

A

T

32
Q

IgA

It protects ________ from attack by bacteria and viruses

Plasma cells that release IgA Abs are concentrated along the ______________

Provides _____ immunity to infants through mothers breast milk

A

mucous membranes

Mucus Membrane surface.

passive

33
Q

IgE

Mediate the immediate ______ reactions (hayfever, asthma, hives, anaphylactic shock)

A

hypersensitivity

34
Q

IgE

Mast cells and basophils bind _________ of IgE

_________ of receptor bound IgE molecules by antigen, induces degranulaltion of the Mast and basophil cells

A

fc portion

Cross-linkage

35
Q

IgE

Parasitic response

Eosinophils express receptors for IgE

T/F

A

T

36
Q

IgD

Found on surface of ______-cells.

Biological function is _______ (thought to function in ____________)

A

mature B

unknown

activation of B-cells

37
Q

Protective function of antibodies

Enhanced Phagocytosis

Antibodies produce resistance by ______ organisms, which make them more readily ingested by phagocytes.

A

opsonizing (coating)

38
Q

Protective function of antibodies

Virus Neutralization

Antibodies directed against specific viral proteins can bind to the virus and block the ability of the virus particle to attach to its cellular receptor. Since the virus cannot ________, it cannot _______.

A

invade the cell; replicate

39
Q

Protective function of antibodies

Neutralization of Toxins—

Antibodies can neutralize toxins of microorganisms (eg, diphtheria,
tetanus, and botulism) and inactivate their harmful effects.

T/F

A

T

40
Q

Protective function of antibodies

__________________ Lysis

______________(ADCC)

Enhanced _________

Virus __________

A

Complement-Mediated

Antibody-Dependent Cell Cytotoxicity

Phagocytosis

Neutralization

41
Q

Primary immune response

When an individual encounters an antigen for the ____ time, antibody is detectable in the serum within ____________, depending on the _____________ of the antigen and the ____________ (eg, oral, parenteral)

A

first

days or weeks

nature and dose

route of administration

42
Q

Primary immune response

The serum antibody concentration continues to rise for _____ and then declines; it may drop to very low levels

The first antibodies formed are ____, followed by _____,______ , or both.

A

several weeks

IgM

IgG

IgA

43
Q

Ig___ levels tend to decline sooner than Ig____ levels.

A

IgM levels tend to decline sooner than IgG levels.

44
Q

Secondary immune response

In the event of a second encounter with the same antigen (months or years) after the primary response, the antibody response is more ______ and __________________________

This change in response is attributed to the _______ of antigen-sensitive “ _________ ” following the first immune response.

A

rapid

rises to higher levels than the primary response

persistence; memory cells

45
Q

Secondary immune response

(More or Less?) IgG is produced, and the level of IgG tends to persist much (shorter or longer?) than in the primary response.

Antibody tends to bind antigen (more or less?) firmly (ie, to have (lower or higher?) affinity) and thus to dissociate (more or less?) easily.

A

More

Longer

More

Higher

Less

46
Q

Active immunity

Active immunity is induced after _________________________ (eg, microorganism or their products).

This contact may consist of _______ or _________ infection,

A

contact with foreign antigens

clinical or subclinical

47
Q

Active immunity

Can be gotten by Immunization with _____ or ______ infectious agents or their antigens,
________ to microbial products (eg, toxins, toxoids), or ________ of foreign cells.

A

live or killed

exposure

transplantation

48
Q

In Active immunity

Host (actively or passively?) produces _________.

Protection is delayed until ___________________

A

Actively

antibodies

antibody production reaches an effective level.

49
Q

Passive immunity

Generated by administration of _________

primary advantage is the ___________________

Useful against certain viruses (eg, __________ virus) after a needlestick injury to someone who has not been vaccinated.

A

preformed antibodies.

prompt availability of large amounts of antibody.

hepatitis B

50
Q

Passive immunity

__________ reactions can occur if the antibody is from another species.

A

Hypersensitivity